Faraaidh of wudhu

Q: During wudhu, if a person forgets to wash a limb and only remembers after washing another limb, what should he do?

Q: A patient is admitted to hospital but not in a serious condition and is mobile. However the patient is given a drip and plaster is used to cover the drip. What is the rule regarding wudhu?

Q: When doing masah in wudhu, should masah be done on the full head (no part should be left out) or part of the head? 

Q: Is the glue used in a plaster waterproof? If I remove the plaster, and after doing wudhu, perform several salaahs, and then find out that the glue is still on my limb, are my salaahs valid or should I repeat them?

Q: If I find some surma in the corner of my eye and it is like one particle which is smaller than sand, do I have to repeat my wudu? 

Q:

1. What are fard acts of wudhu? If I want to wash my face and there is some sweat on my face, can I make my hand wet then wipe my face or washing my face is required?

2. Also, if I were to wash my arms or face, normally I wet my hand and touch the tap to close it and wipe my face after touching tap. The tap was wet due to me closing it, so is my wudu valid since my hand had mustamil (used water )?

3. Also when doing masah, if my hand touched my wet face and that water also came in doing masah is my wudu valid? (Here also mustamil water)

4. Is doing wudu in steps compulsory or not?

5. Is it compulsory to complete the wudu before the hands and face get dry?

Q: If someone has applied henna and wants to perform wudhu, should one remove a covering bag and wipe the head, still covered with henna, or can one wipe over the covering itself.

Q: If someone applies henna on the head and then covers the head with a polythene bag, will it be permissible to do masah on the head during wudhu?

Q: During wuzu is it farz to wash the face from the hairy part of the forehead? A person whose hair grows above the forehead due to baldness then from which part of the forehead is it farz to wash the face?

Q: Are the hands, including the wrist, included in the faraaidh of wudhu?